National security correspondent

Immigration Minister Scott Morrison has brushed aside claims by Papua New Guinean police that Australia has hampered the investigation into fatal riots on Manus Island and may even have perpetrated a ''major cover-up''.

PNG's deputy police commissioner, Simon Kauba, issued a furious statement on Wednesday insisting police on Manus Island played no part in the violence - directly contradicting the findings of Australia's official report.

In a remarkable series of claims that underscore the gulf between PNG authorities and the Australian government, Mr Kauba attacked the ''lack of co-operation'' from Australian government agencies and said the report by Robert Cornall ''hampers our ongoing investigations''.

Separately, a PNG police spokesman, Dominic Kakas, said one of the four chief suspects in the killing of Iranian asylum seeker Reza Barati had fled Manus Island and his whereabouts were unknown.

Advertisement

Most strikingly, Mr Kauba said the PNG police ''did not enter the detention centre either before or during the disturbance and were not involved in the riot, nor were they responsible for inflicting any injuries sustained by the asylum seekers''.

This is despite Mr Cornall saying in his report that he saw bullet holes at chest height in the walls of the centre - a claim backed by photos published previously by Fairfax Media.

G4S guards and other workers in the centre are not armed with guns, but PNG police, notably the ''mobile squad'' officers, do carry them.

Mr Kauba also cast doubt on whether an asylum seeker had been shot in the buttocks as stated repeatedly by Mr Morrison and confirmed by the Cornall report.

He said injured asylum seekers had been ''secretly flown into Port Moresby and put up at a hotel''.

PNG police knew only from media reports about the claims that one of them had been shot, he said.

''The only way we can confirm this is if the injured man is brought forward and appropriate tests conducted to confirm the nature of the injuries sustained,'' he said.

''Otherwise this whole matter stinks of a major cover-up.''

Mr Morrison fully endorsed the Cornall report when he released it on Monday - including the finding that PNG police entered the detention centre and took part in the violence, which the police have since denied.

On Thursday Mr Morrison was asked whether he still had confidence that the PNG police could deliver justice over the violence, including the killing of Mr Barati.

''The police investigation is a matter for PNG authorities,'' he said.

''It is a matter for those authorities to lay any charges and to proceed with prosecutions.''

He said Australia had committed to provide any help the PNG authorities needed with their investigation.

And he hit back at Mr Kauba's claim that the Cornall report had interfered with the PNG police investigation, saying Australia had fully informed the PNG government of the release of the report.

The PNG Foreign Minister issued a statement about the same time stating that the release of the Cornall report ''had not come as a surprise because the PNG government was fully briefed on the findings of the review''.